Effects of Boron Carbide Content on the Microstructure and Properties of Atmospheric Plasma-Sprayed NiCoCrAlY/Al 2 O 3 -B 4 C Composite Coatings

NiCoCrAlY/Al 2 O 3 and NiCoCrAlY/B 4 C composite powders were prepared with hydrogen reduction and solid state alloying process. NiCoCrAlY/Al 2 O 3 -B 4 C composite coatings with different contents of B 4 C were prepared by atmospheric plasma spray technology. The microstructures, mechanical properties, and tribological properties of the composite coatings with different B 4 C contents were systematically investigated. The results show that the microhardness of the composite coatings increases, while the tensile strength of the composite coatings decreases, with the increase of B 4 C contents. The wear volume of the composite coatings decreases from room temperature to 800 °C with the increase of B 4 C contents. Abrasion wear is the main wear mechanism of the NiCoCrAlY/Al 2 O 3 -B 4 C composite coating from room temperature to 800 °C.